1. Technical Field
The invention relates to a backlight unit, and more particularly to a backlight unit having reduced flickers.
2. Related Art
A liquid crystal display (hereinafter, referred to as “LCD”) device is frequently used due to characteristics of lightness, slimness, low driving power consumption and so on. The LCD device is used in various fields such as office automation equipment, audio/video equipment, etc. The LCD device controls the transmitted amount of light beam in accordance with a video signal applied to a plurality of control switches which are arranged in a matrix shape. As a result, a desired picture is displayed on a screen.
The LCD device is not a self luminous display device, and it requires a light source such as a backlight. A backlight unit for use with the LCD device includes red, green and blue light sources that emit red light, green light and blue light, respectively. The red, green and blue lights are mixed to generate a white light.
The red, green and blue light sources may be controlled by a pulse width modulation controller (hereinafter, “PWM controller”). The PWM controller includes three separate and individual controllers that control the red light source, the green light source and the blue light source, respectively. The PWM controller may be large in size because of the separate red, green and blue PWM controllers. Further, the PWM controller generates separate control waves that drive the red light source, the green light source and the blue light source. The control waves may not be synchronized, and as a result, red, green and blue light emitting driving signals Rds, Gds and Bds are not synchronized as shown in FIG. 1. Flickers may generate due to the asynchronous drive timing of the red, green and blue light sources. Accordingly, there is a need of a backlight unit that overcome drawbacks of the related art backlight unit.